


Plokámia

by alxndrlightwoods



Category: Shadowhunters (TV)
Genre: Aftercare, Anal Sex, Begging, Choking, Cock Warming, Come Inflation, Consentacles, Crying, Dirty Talk, Dom Magnus Bane, Dom/sub, Double Penetration, Hand Jobs, Kink Negotiation, M/M, Magnus Bane Has Tentacles, Oral Sex, Overstimulation, Risk Aware Consensual Kink, Sounding, Sub Alec Lightwood, Subspace, Tentacle Sex, Tentacles, Urethral Play, funishment
Language: English
Status: Completed
Published: 2019-06-12
Updated: 2019-10-07
Packaged: 2020-05-01 20:22:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 7,472
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19184905
Author URL: https://archiveofourown.org/users/alxndrlightwoods/pseuds/alxndrlightwoods
Summary: There's nothing in Magnus's file about his second warlock mark. The strange, blackened skin that runs down the length of his spine. The file isexhaustive, so it makes no sense.Alec really wants to know about Magnus's second mark, because it's clearly asecretand Alec likes being trusted with Magnus's secrets.





	1. Chapter 1

**Author's Note:**

  * For [lynne_monstr](https://archiveofourown.org/users/lynne_monstr/gifts).



> There's no tentacle fic? I guess? So I fixed it.

Alec had noticed it the first time they’d been in bed together, when he’d run his hands down Magnus’s back and felt a  _ difference _ in the skin over Magnus’s spine.

Magnus had reacted like he’d been electrified, moaning at the touch, and after, well. Alec had taken the opportunity to get a look at Magnus’s back, at what was  _ clearly  _ a second warlock mark.

Alec has no idea what it is, and Magnus hasn’t said anything, not once, even though Alec takes advantage of the sensitivity of it at every available opportunity.

The strange, blackened skin starts at the knob of his spine and continues down to the small of his back, a little rougher than the surrounding skin. Magnus always shivers and jerks when Alec runs his fingertips lightly down his spine, and when Alec  _ digs his fingers into it, _ he gets  _ frantic. _ Alec always ends up roughly used and  _ wrecked _ when he does that, which is why he does it all the time.

But he’s curious. There’s nothing in Magnus’s file about it — and there  _ won’t be —  _ but… Alec really wants to know. He wants to know  _ everything _ about Magnus. He knows that’s, logistically, impossible, but it doesn’t change his ravenous appetite for it.

The worst that can happen, if he asks about it, is that Magnus will say no. He knows this, because Magnus promised that he’d never be upset with any questions Alec decided to ask him about himself or his past, so at most, he gets shut down.

It still takes him a while to work himself up to asking, but he’s worked up the nerve now. 

It’s his day off.  _ Their _ day off, because Magnus refuses to work — barring emergencies — on Alec’s days off. So this is a perfect time to ask; if he accidentally trips over something bad with this question, he has time to make it up to his boyfriend.

“Magnus?” he says, and Magnus looks over at him. They’re curled up on the couch together, some stupid cooking show going in the background — stupid in that the people in it are stupid, Alec actually enjoys making fun of the contestants on it — but mostly they’re just cuddling. Now that Alec has Magnus’s attention, he asks “What’s with your second mark on your back?”

Magnus goes very very still next to him. “Ah,” he says, after a few moments. He clears his throat before continuing. “It’s not a mark.”

Alec raises a brow, twisting so he can see Magnus’s face better. “I’m pretty sure that’s a warlock mark, Magnus. Unless you want to tell me something really weird about magical tattoos.”

Magnus’s lips twitch as he fights off an amused smile. “It’s not a mark, darling, I’m serious. It’s just a side effect of the amount of magic I have.”

“A side effect,” Alec repeats doubtfully.

Magnus is blushing, Alec realises. “Magnus?” Alec questions, fascinated. This is not how he expected this conversation to go and he’s even  _ more  _ interested now.

“It’s a bit of demonic anatomy that any warlock at or over a certain level of power is born with,” Magnus says. “It’s… you might have noticed that some warlocks have demonic parents that… aren’t precisely compatible with humans?”

Alec nods, and Magnus continues. He’s still blushing, but it’s fading, the somewhat academic nature of his lecture easing some of his apparent embarrassment. “Some of them are capable of shapeshifting or taking on a human form, but most aren’t. So, all demons have a bit of shared biology, one that makes it possible for them to interbreed with humans. The ability to manifest penile like appendages for… breeding purposes.”

Alec doesn’t put it together for a few seconds, and when he does, he realises why Magnus was blushing.

“Tentacles,” Alec says, incredulous. “You’ve got  _ tentacles _ in your back?”

Magnus’s blush is back and he’s looking away from Alec, unable to meet his eyes. Which… considering what Magnus had told him about how people had reacted to his eyes, Alec can see why he’s nervous. It’s for nothing though. Alec loves every part of Magnus.

“They’re not in my back, that’s just where they manifest from. They’re magical, they’re not actually  _ in _ my body, that’s just where they grow from.”

Alec’s heart is pounding. He feels flushed, and he’s blushing too, he thinks, because… Magnus has just confirmed that he can grow tentacles. Tentacles that exist for the express purpose of sex.

“That’s…” he trails off, not sure what he wants to say. “Can I see?”

“Ah,” Magnus says again. “They’re — Alexander, they’re not really… something I can just show you then put away again.”

Alec is  _ definitely _ blushing. “I—” he says, then stops, because he doesn’t know how to continue that sentence.

“Alexander?” Magnus says, eyes widening as he studies Alec’s face.

“I mean, that’s fine,” Alec says, licking his lips. There’s no way it’s not completely obvious to Magnus that Alec is  _ into it, _ the idea of Magnus fucking him like that.

“You’re serious,” Magnus says, slowly.

Alec licks his lips again. “I mean, you did just tell me you’re solely capable of playing out my gangbang fantasy,” he says, ignoring the curl of anxiety and shame in his gut.  _ Magnus _ is the last person who is going to judge him for a sexual fantasy.

Alec bites his lip when, in response to Alec’s words, Magnus’s control on his glamour fades as he makes a punched out breathless noise.

_ “Alexander,” _ Magnus says. “Darling, you can’t just do this to me while we’re having a serious conversation.”

“Do what?” Alec asks, slyly. “Tell you I love every part of you and I’m interested in getting up close and personal with every bit of you?”

Magnus’s eyes flash. “Bedroom,” he orders, and Alec scrambles off the couch to obey, because he doesn’t want to risk Magnus changing his mind.

Magnus follows him at a more sedate pace, stripping off his shirt as he joins Alec in the bedroom. He tosses it carelessly aside, because he knows that it gets Alec hot under the collar when he takes off his clothes the  _ normal _ way instead of with magic. Alec can't even explain it properly, even though he’s tried when Magnus had asked him about it; there’s just something about how Magnus  _ looks _ when he’s stripping off his clothes that makes heat coil in his belly.

“Bed,” Magnus says pointedly, and Alec stops hovering next to the bed to settle on it, instead.

Magnus stops in front of him, close enough to touch, and then the air around him  _ ripples. _ The tentacles really do  _ grow _ from his spine, from what Alec can tell, because they don’t just appear, instead creeping into sight over Magnus’s shoulders, around his ribs.

There are a lot of them, enough that Alec can’t get an accurate count at a glance, and they’re all different sizes, some of them not even as thick as a finger, to a few that look like they’d need an entire  _ bottle _ of lube to work their way into someone’s body.

Alec’s mouth is dry. “Magnus,  _ by the angel,” _ he says, breathless.

Magnus is smirking. Several of the tentacles move forward in a clear invitation to touch. Alec does,  _ eagerly, _ puts his hands on two different ones, too curious to find out what they feel like to ask if Magnus is sure.

They’re leaking sticky, clear, fluid from the tips, and they don’t really look like dicks — the tips are blunt and smooth, with no discernable ‘head’ — but they feel mostly the same.

They’re leaking a  _ lot. _ Alec isn’t sure if it’s because they just do that or because they’re sensitive.

Another one ghosts up his arm, leaving another trail of sticky fluid, continuing up until it brushes across his lips. Alec flicks his tongue out in an attempt to lick it, but Magnus pulls it away, teasing. Alec makes a noise of frustration and starts to lift his hand so he can pull it back, but the tentacles he’d been holding wrap around his wrists, stopping him from moving.

“Did you want a taste, Alexander? Or maybe for me to fuck you with them?” Magnus asks, amusement evident in his tone.

“Yes,  _ please,” _ Alec says, straining against the tentacles preventing him from moving his hands. They don’t give at all. Alec lets out a whine, half frustration and half arousal. He wets his lips, tasting the salty, bitter fluid left on them from the brief brush of the tentacle over them.

A few more of them repeat the action, brushing against his lips, never giving him a chance to predict which one is going to touch him next. Alec endures it for a few passes before opening his mouth in invitation. One presses against his bottom lip and hesitates before pressing in, against Alec’s tongue. Alec curls his tongue up, moaning, but Magnus pulls it away before he can get a proper taste.

They’re in reach now, though, if Magnus doesn’t move them back again, all Alec has to do is lean forward — 

“Alexander, darling,” Magnus says, breathless. “I really do need more from you than ‘yes, please’.”

The only response Alec has for him is a  _ moan.  _ This is  _ unfair. _ Magnus has been hiding this — this  _ mark, _ because it may be something any warlock of sufficient power can have or  _ do _ but  _ it’s a mark — this _ from Alec, and now he wants Alec to — what? String more than two words together? That’s not happening. At all.

Instead he leans forward a little and wraps his lips around the closest tentacle, tastes a burst of salty liquid across his tongue. Magnus makes a growling noise that makes Alec wish he had his eyes open to see the expression on his face.

The tentacle pushes deeper into his mouth, and he’s not sure if it’s on purpose or not but he’s  _ not complaining. _

It’s different than a dick. It’s sinuous and  _ muscled _ in a way a dick isn’t, and this one in particular is smooth but some of the others he saw  _ aren’t.  _ He moans again as the tentacle hits the back of his throat and — and.  _ And. _ It’s longer than a dick —  _ much _ longer, and it reaches the point where Alec is used to someone  _ stopping _ and  _ keeps going. _

He’s never been more thankful for his lack of gag reflex than right now, because he doesn’t choke. He also doesn’t get to find out how it feels to have his throat fucked like this, because the tentacle swells —  _ fuck —  _ and pulses, spilling down his throat.

Alec expects — well. He, for some reason, expects this to work like human anatomy, so he’s expecting Magnus to pull it out, but instead, he  _ does _ get to find out what it feels like to have his throat fucked. He feels tears start to gather in his eyes and he moans again.

Then the tentacle slithers it’s way out of his throat and Alec almost  _ cries. _

“Magnus, what,  _ no—”  _ he begs, voice hoarse. He opens his eyes, searching for Magnus, and he knows he probably looks — and sounds — desperate but he doesn’t care.

“Just a minute, darling, I promise,” Magnus says, his own voice unsteady, the  _ many _ tentacles that have grown from that strip of skin down his spine moving sinuously through the air.

“Whatever you’re making me wait for better be  _ really—”  _ Alec starts, but Magnus  _ moves _ and what he’d been saying gets lost. He ends in Magnus’s lap, both of them on the bed, with no clear idea how they got there. He’s pretty sure magic was involved.

Either that, or whatever liquid the tentacles are secreting — which is smeared on his palms and forearms, from where Alec had first touched them and from where Magnus had had him  _ restrained —  _ has some sort of effect.

Or maybe it’s all the demonic come Magnus just spilled down his throat. His mouth waters just thinking about getting an actual  _ taste. _

“I want you right here, my darling,” Magnus whispers against his mouth, hands firm on Alec’s hips, “while I fuck you. I want to feel you pressed against me,  _ writhing _ in my lap, as I fill you up.”

Then Magnus kisses him, and Alec loses time or awareness again, because he’s moaning desperately, even  _ more _ turned on, as Magnus sucks on his tongue, and his clothes are gone.

Several of the tentacles are sliding across his body, and they’re wrapping around him like living bondage. Magnus has, at least — or, he thinks Magnus has, he’s a little unclear on if these things have a little bit of a mind of their own or not — positioned the ones circling his wrists so that Alec can wrap his hands around the tentacle so he’s not grasping at air.

They’re wrapped around his ankles and thighs, too. And it’s… different. Magnus has restrained him with actual restraints before,  _ and _ with magic, but this feels… like  _ more. _

“Remember your safeword, darling?” Magnus asks, pressing soft kisses to Alec’s mouth.

“Mmm, yeah,” Alec agrees. Several tentacles are sliding over his shoulders and down his back, leaving more stick trails, and there's  _ definitely _ something in them, because he feels hot all over, and the sensation gets more intense with each brush of fluid.

_ “Good,” _ Magnus says, and then his mouth is full again, this time with  _ two _ tentacles, both smaller than the previous one. Alec is confused about why until he  _ isn’t. _

They’re moving out of time with each other, one sliding down his throat, further than Alec is used to, again, and the other just fucks his mouth; Alec can’t even suck on the one that’s staying in his mouth because he can’t do anything but  _ take it, _ the sensation of someone fucking his mouth and his throat — the combined sensations leaving him off balance and gasping.

There is a teasing press at his hole, more than one slim tentacle pressing against his rim, slowly loosening him up with their touches and lubing him up with the pre-come they’re  _ dripping _ with. One finally presses  _ in _ and instead of teasing more, Alec feels a rush of hot liquid as it pulses, coming in him.

It presses into him a little more with each pulse,  _ opening him up _ as it spills in him, using the come to slick itself in further. It fucks him shallowly, glancing off his prostate, and Alec swallows as much as he can around the tentacles, saliva pooling in his mouth.

He has enough brainpower to tap lightly on the tentacle in his hand with two fingers.

The two in his mouth immediately pull out, and Alec swallows the rush of saliva in his mouth properly before trying to speak.

“Alexander?” Magnus says, questioningly. Which is reasonable — Alec doesn’t use  _ any  _ of his safewords often, and he’s very clearly not in distress at the moment so Magnus is understandably confused.

“Can you just come whenever you want with those?” Alec asks when his mouth is clear.

There is a moment of silence before Magnus answers. “Yes,” he says, eyes searching Alec’s face.

A full-bodied shudder goes through Alec at the confirmation.

“You’re gonna, right?” Alec asks, clenching down on the tentacle still in his body. He can feel it twitch when he does, but Magnus keeps it still. “Fuck, Magnus, that’s what you meant, right?”

“That I would fill you up with come, darling?” Magnus asks, relaxing. One of the tentacles he removed from Alec’s mouth presses against his lips and Alec licks the tip. The knowledge that it could be filling up his mouth with come  _ right now _ if Magnus decided to  _ do that _ is  _ so hot.  _ He licks it again, and even though he knows Magnus won’t slip it back into his mouth, he  _ wants Magnus to. _

_ “Please,” _ Alec begs, because the thought of being filled up — with cocks  _ and _ come — is a fantasy he’s had for  _ a while, _ one he never thought he’d get.

_ “This _ is a secret you’re going to pay for keeping, later, by the way” Magnus murmurs, pulling the tentacle back out of reach and kissing him again. “But yes, darling, that’s what I’m going to do.”

Then the tentacle Magnus had moved out of Alec’s reach is pressing against his mouth again, and Alec parts his lips to let it in. Alec lets his tongue swirl around the tip as it prods his mouth, curious, and then Magnus makes good on his promise and Alec’s mouth is being filled with come.

It’s bitter, but whatever it is about this that makes it  _ different _ has his body wired to crave the taste, so he swallows it down greedily, even as Magnus puts his fingers on Alec’s chin, tilting his head back so it’s easier to swallow, so less drips down his chin. Alec can’t help the little moans he’s making, eyes closed as he drinks as much of it down as he’s able.

His whole body is screwed up tight, but that doesn’t stop another tentacle from working it’s way into his ass, then  _ another, _ and they’re only a bit bigger than Magnus normal is, even with there being three of them, but they can all move independently while still leaving him  _ full. _ The only thing stopping him from fucking himself on them while they fuck  _ him _ is the fact that Magnus — with his body and hands and arms and  _ tentacles —  _ has him pinned, unable to move.

“This isn’t the first time I’ve done this,” Magnus says conversationally, brushing his thumb through the come still dripping down Alec’s chin, the tentacle in his mouth  _ still pulsing, _ “but I forget, every time, how  _ good _ this feels.”

Alec moans again at the implication, that this is going to happen  _ again _ at some point. It’s already so hard to think, because he feels full and  _ hot, _ even as the steady pulse of come spilling into his mouth tapers off and the tentacle starts fucking his mouth again, thrusts matched to one of the  _ others _ fucking him.

“Such a good boy,” Magnus says, as he moves his hand away from Alec’s waist, a thicker tentacle wrapping around his hips to hold him in place. It’s hard to keep track of how many are touching him because they’re  _ everywhere.  _ More pressing against his entrance, one teasing the seam of his lips where they’re already stretched around the one in his mouth, leaving a stick trail down his cock to press behind his balls.

Alec whines and comes, cock mostly untouched. As he does, the one wrapped around his waist tightens and moves, the end of it wrapping up and around his cock and the head of it pressing firmly against his slit. Alec jerks and shouts, noise muffled by his  _ full mouth, _ and Magnus gives a pleased hiss beneath him.

The tentacle around his cock constricts in time with the ones fucking him, wringing his orgasm out of him for much longer than Alec thought possible.

“I could fuck you like this for hours,” Magnus says, “but I have a better idea.”

Alec makes a protesting noise, because while Magnus always has good ideas, the prospect of being fucked like this for  _ hours _ is definitely what he wants right now.

“Don’t you trust me, darling?” Magnus says, as the tentacle wrapped around his cock coils around the head, completely covering it and squeezing. Alec’s back bows at the sharp pleasure, accidentally biting down on the one in his mouth, but it doesn’t seem to hurt Magnus, thank the angel.

Alec hopes that was rhetorical, both because of  _ course _ he trusts Magnus, and because he can’t exactly talk right now.

He doesn’t notice anything different at first, other than another slim tentacle starting to ease it’s way into his hole to join the three already in him — one of the others filling him with come to ease the way — but then the one in his mouth fills his throat  _ up _ the next time it presses in, instead of just sliding in smoothly.

It’s getting bigger, he realises. It’s  _ growing _ while Magnus fucks his mouth with it. He hollows his cheeks as best he can next time it pulls out, letting his tongue drag along the underside, and this time, he can  _ feel _ it get heavier on his tongue, feel it stretch his jaw more.

Magnus makes a pleased humming noise, almost lost under the noise Alec makes at the realisation that Magnus can, apparently, control the size of the tentacles he’s manifested.

And is, in fact, doing that to one of them while he fucks Alec with it.

It keeps swelling and growing until Alec’s jaw  _ aches _ with it, until it has to work its way in and out of his throat inch by inch.

He can barely breathe,  _ can’t _ think, can’t even make  _ noise _ with how full his mouth is. He thinks he hears Magnus murmur something, something about how he’s taking it so well, but it’s just snatches of sound.

He feels overwhelmed, teetering on the edge of sensory overload, and then Magnus wraps his hand around Alec’s throat and  _ squeezes. _

Alec feels like he’s underwater, pulse rushing in his ears as he forgets how to breathe, every cell in his body electrified. His eyes roll back in his head as the tentacle has to force its way through Magnus’s grip around his neck. 

Magnus doesn’t stop. Alec can’t stop shaking as his throat is forced to open up again and again, the thick length of the tentacle pushing past Magnus hand over and over again, short, aborted thrusts.

Magnus leans forward to put his lips on Alec’s throat, above his hand wrapped around it, and Magnus moans against Alec’s skin as he feels Alec’s throat move. Alec is being used for Magnus’s enjoyment right now — Magnus is fucking Alec’s throat like this so he can  _ feel _ it against his palm, he’s doing  _ exactly this _ because it’s what  _ he wants to feel —  _ and Alec comes again with a soundless scream.

His entire body locks up, and so do all the tentacles touching wrapped around him and  _ in _ him. The ones wrapped around his limbs and cock squeeze, the one around his cock tightening to the point of  _ almost pain _ and no further, and it — and the ones in him — all start to spill.

The feeling is too much. It’s too — they’re all pulsing rhythmically, in time, and Alec is  _ overwhelmed,  _ can’t concentrate on any one sensation for more than a second at a time — 

The feel of the one wrapped around his cock, pressed firmly against his slit as it comes in time with him, Magnus’s come  _ hotter _ than his own and dripping  _ into _ his cock for a bare moment before Alec’s own come pushes it out, only to repeat;

The  _ rush _ of come in his ass, the four that Magnus had put in him coming  _ much more _ than any  _ one _ could ever manage, and the fact that there’s  _ so much _ that even with his hole stretched  _ tight _ around them so much of it  _ spills out; _

The one in his throat, which is… 

The head of it is aligned perfectly with the center of Magnus’s palm, by the feel of it, and each time it pulses, each time Alec manages to take a desperate breath, he can feel Magnus’s heartbeat in it.

The one in his throat doesn’t  _ stop. _ Not even after most of the others do, possibly  _ minutes _ later, Alec doesn’t have a sense of time right now; Magnus  _ keeps coming with it. _

Alec’s world has been overtaken by the sensation of it gently shivering and twitching between his lips, his pulse pounding in his cheeks, the way the tip of it  _ moves _ just slightly with every spurt of come.

He’s vaguely aware of Magnus talking again.

“So good, darling, Alexander, you feel  _ so good,” _ Magnus says, repeating variations of it over and over, eventually letting Alec put it together and make sense of it.

“So fucking good,” Magnus says, pressing another kiss to Alec’s throat, running his fingers along Alec’s lower lip where it’s stretched against the tentacle, before he removes his hand from Alec’s body entirely.

It doesn’t matter, anyway, because the only point of contact Alec has with the rest of the world is Magnus’s hand wrapped around his throat.

Alec hadn’t spared a thought to wonder what Magnus had removed his hand to do because he doesn’t really  _ have _ thoughts right now, but he finds out anyway, because the tentacles in his ass pull out of his body and Magnus replaces them with his cock.

Alec is loose and Magnus’s cock slides  _ right in _ with no friction, even when Alec clenches down. He’s loose enough that Magnus slides two fingers in next to his cock and it’s  _ still  _ not a stretch, not until Magnus adds a third. Fuck, he’s so  _ wet _ from all the come Magnus had filled him with, so stretched out from getting fucked the way he had.

Magnus isn’t fucking him now, though, just has Alec keeping his cock warm as he comes and comes and  _ comes _ down Alec’s throat.

He’s so full. He wonders if his stomach is showing the evidence of the amount of come in him, wonders if he would be able to  _ feel it happening _ if he had his hands free and checked.

It’s so hot.  _ He’s _ so hot, he feels like he’s on fire, almost, like he’s taken a shot of hard liquor and it’s burning his way down his throat to settle in his core. 

He must be making a mess of Magnus and the bed, with all the come dripping out of him. It makes him want to moan, how it must feel for Magnus to have that burning hot come surrounding his cock and leaving hot trails all over his thighs, staining his clothes.

Alec’s cock is still twitching, wrapped up tight, and that one is still coming too, just slower. Several seconds pass between each slick pulse of come against his slit where the heads are kissed together, and it almost feels like  _ Alec _ is coming every time it does, with how they’re pressed together.

Magnus pulls his fingers free, leaving Alec  _ loose _ again, and runs them, slick with come, across Alec’s cock and the tentacle wrapped around it. “Maybe I’ll fill you up here next time, too, darling. Would you like that?”

Whatever little brainpower Alec still had  _ disappears _ with that question. Alec can imagine it, viscerally, how it would feel if Magnus made one of his tentacles  _ smaller _ and pressed it  _ into _ his cock, the way he’s almost threatening to now; the only thing stopping it from happening currently the issue of size. How it would feel to have it spend itself directly in his cock, how good it had  _ already _ felt, but  _ deeper. _

Magnus skitters his fingers around the head of Alec’s cock, just as the tentacles pulse again, in concert, the one in his throat matching the timing of the one wrapped around his cock.

“I’m going to make it so there is  _ no part _ of you I haven’t reached,” Magnus murmurs, rubbing his thumb along the line of the tentacle making his throat bulge as he slides his other thumb between the tentacle and Alec’s skin, pressing firmly just below the head of Alec’s cock.

Alec can’t get enough air in his lungs as he comes, vision going hazy and soft around the edges as Magnus’s grip on his cock and his throat tightens, everything slow and hot and  _ wet _ and Alec feels like he’s passed out, like his brain is just  _ off _ even though he’s still vaguely aware of things.

Magnus keeps him like that for — Alec doesn’t know how long. He’s slumped in Magnus’s lap, pliant, held upright only by the tentacles restraining him. Magnus has removed his hand from Alec’s softening cock, although the tentacle is still wrapped gently around him, and the one in his throat has shrunk down enough that it slides out of his abused throat easily.

Alec feels so full and contented that he doesn’t even protest.

He blanks out a little — still aware, nominally, but  _ not processing —  _ and the next thing he's not blank on is Magnus curled around him. The sheets aren’t wet, and Alec isn't dripping with come anymore, but he’s still slick around where Magnus has his half-hard cock in Alec’s hole still.

Magnus has a hand pressed to Alec’s stomach, making Alec wish he had enough control over his body to  _ look  _ and see if there is physical evidence of how much Magnus came in him.

Magnus is plastered to his back, leaving Alec feeling warm inside and out.

“With me, darling?” Magnus murmurs against his neck. 

Alec tips his head back a little and hums in agreement. He doesn’t think he can  _ move _ right now, but he can definitely think again.

“Next time,” Magnus whispers softly, lips brushing against the shell of Alec’s ear, like a secret, “I’m going to leave your mouth empty and fill up your pretty cock. I can’t  _ wait _ to hear the noises you make.”

Alec is  _ definitely _ not capable of getting hard again, as blissed out as he is, but Magnus’s words make him shiver.

He’s already looking forward to the promised  _ next time. _

**Notes for the Chapter:**

> the stupid cooking show is cutthroat kitchen, which is both ridiculous and a delight.


	2. Chapter 2

**Summary for the Chapter:**

> “Sounding,” Magnus says firmly. 
> 
> “Is that what it’s called?” Alec asks, to stall.

**Notes for the Chapter:**

> chapter two is gifted to lynne_monstr for having so many awesome tentacle ideas, all the time. also fits for day 6 of Tentacletober (Tentacle Sounding), so enjoy.

When Alec wakes up sometime later, it’s nighttime. He’s been unconscious for a good few hours, considering it’d been late in the afternoon when he’d started his, ah,  _ conversation _ with Magnus.

He feels fine. Not sore, not tired,  _ energized, _ even.

“Mm, awake now darling?” Magnus says, from where he’s still plastered to Alec’s back. Alec shifts a little, and the movement causes him to realize that Magnus’s cock is still in him.

He shivers, because he always loves when Magnus just casually uses his body like this, keeps them  _ together _ in ways that don’t involve sex.

“Yeah,” he says, settling back down and closing his eyes again. “Did you clean me up while I was asleep?” he asks, because he’s not  _ full _ anymore, either.

“Mmm,” Magnus hums, rubbing his hand over Alec’s stomach. “No, your body absorbed it while you slept.”

Alec blinks his eyes open. “What—” he starts but no that… makes a disturbing amount of sense. He debates saying ‘gross’ on principle, even though he doesn’t think it’s gross.

“It’s for healing purposes,” Magnus says, when Alec doesn’t continue. Ok, Alec hadn’t realised  _ that _ but that… also made sense.

“I wasn’t hurt,” Alec says, because while Magnus  _ probably  _ knows that, that doesn't change the fact that Magnus had  _ probably _ been worrying, while Alec was asleep.

Magnus presses a kiss to the back of his neck.

“We need to have a discussion,” Magnus says after a few minutes. Alec wants to make a protesting noise but he knows Magnus is right.

“I’m not moving,” he warns. He’s comfortable and if they’re going to have a discussion about kinks and limits he wants cuddles.

“So, a gangbang fantasy,” Magnus starts. “Is that a ‘this gets me off really good’ fantasy, or a ‘oh I want this to happen to me’ fantasy?”

“The first one,” Alec confirms, resisting the urge to squirm.

“Tell me about it?” Magnus asks, and… 

Alec knows Magnus means that he wants to know  _ why _ Alec has this fantasy, not the details of  _ how _ he has it.

“It’s…” Alec says slowly, trying to push back his instinctive urge to  _ not talk about what he wants, _ “You know that I like… like being used. People making themselves feel good using me is just…” he cuts himself off with a shiver, feeling Magnus harden in him in response.

Magnus presses another kiss to the back of his neck and presses his hand more firmly to Alec’s stomach. “I did know that about you, yes,” Magnus agrees. “I just wasn’t sure if you were using ‘gangbang’ when you really meant ‘orgy’.”

“Orgies are everyone having sex with each other, I want everyone to have sex with me,” Alec says, because he knows it’ll make Magnus laugh.

He does, burying his face into Alec’s hair and giggling, and Alec bites his lip to keep from joining him.

Then he has to bite his lip to hold in a moan with the way they’re shifting.

“Magnus,” he groans, rolling his hips back a little. He got fucked so good he passed out a few hours ago but he’s already aroused again, wants Magnus to fuck him.

“Not yet, darling,” Magnus says, calming himself and stilling Alec’s hips. “We’re not done.”

What could they have to talk abou— oh. Right.

“Sounding,” Magnus says firmly. 

“Is that what it’s called?” Alec asks, to stall.

“Technically sounding involves a specialised sex toy, but the principle is the same, yes,” Magnus says. “And usually there’s no, ah, there’s usually nothing going in  _ but _ the toy.”

Alec stays silent.

For too long, apparently.

“If you were agreeing in the heat of the moment, Alexander, there’s nothing wrong with that. Just like there’s nothing wrong with wanting to try it — either with the toy or like earlier.”

“No, I…” Alec says, “I liked the idea. Of you… filling me up.”

He’s blushing. He’s  _ so _ glad Magnus can’t see.

“Sounding is usually something you have to be careful with,” Magnus says, in what Alec is hoping is a roundabout answer. “If you get too rough it can be painful or even damaging. With me, though… my come is designed to have healing properties, among other things, and the magic lets your body accept the penetration easier, in ways that you normally wouldn’t be able to take.”

“I want it,” Alec says, when Magnus stops. “If it’s safe — I want to try.”

“I’ll never push you past what your body can’t handle if I can help it, Alexander,” Magnus says. “What  _ you _ could handle. If I didn’t think it was safe, I wouldn’t offer.”

And it’s not like Alec will be shy about using his safeword if things get out of hand. 

He can just… take a  _ lot, _ though. And he wants to take this.

“Please,” Alec says, tilting his head back and turning so his lips brush against Magnus’s.

“Darling, you’re insatiable,” Magnus groans, rolling his hips against Alec’s, hands still firm on his hips, holding him still.

“I blame you,” Alec says, before his breath catches and he has to swallow at the sight of the tentacles creeping over Magnus’s shoulder again.

One of the smaller ones — not one of the  _ smallest —  _ slides down to wrap around his cock as Magnus lifts a hand to press gentle fingers to his jaw, bringing their lips together in a soft kiss. Alec tries to roll his hips up but there’s a thick tentacle wrapped over his hips, keeping Alec in place, and Alec parts his lips with a moan.

Magnus presses his tongue inside, deepening the kiss, and Alec doesn’t realise that he’s being prevented from  _ looking  _ until there’s a gentle tease at the head of his cock and Magnus’s palm cupping his face prevents him from turning his head.

“Magnus,” he gasps out, breaking the kiss and opening his eyes, only to be greeted with the sight of Magnus’s unglamored eyes and a gentle smirk.

“You didn’t think you could get away with blaming me for something without a consequence, did you darling? And I did say you’d pay for keeping things from me…” he trails off, even as he wraps his free hand around Alec’s cock and rubs his thumb under the crown.

Alec whines and tries to arch up into his touch, but the tentacle holding him down flexes hard and heavy across his waist. There’s another teasing touch at his slit and Alec wants to look  _ so badly. _

The press of it is gentler than he thought it would be — not that he’s thought about it much, hadn’t known it was a  _ thing _ for long — but the tentacle is… small.  _ Thin, _ not enough to hurt, even without magic easing the way. The sticky fluid all the tentacles leak is making the slide in  _ easy _ and Alec can already feel the effect it has on him.

His cock is hot and throbbing under the grip of Magnus’s hand and the tentacle wrapped around it, his pulse pounding under Magnus’s fingers as the slim tentacle slowly slides down his cock.

“Would you like me to fuck your cock like this, Alexander?” Magnus murmurs, voice low and conversational. Alec forgets how to breathe. “I think you’d like that, darling. Work your cock a bit from the inside?”

Alec can’t help but moan at the idea, Magnus  _ fucking his cock, _ the tentacle dipping in and out of his slit. It already feels amazing, slick and  _ hot _ inside, body torn between how strange it feels and how  _ good _ it is. Magnus is so deep inside his body, in a way that no one else can or ever will be, and he’s already on the verge of coming just from the  _ idea  _ of it.

“Ask nicely,” Magnus says, when Alec still doesn’t answer, because Magnus  _ knows _ him, knows what he wants, and gives it to him, always.

And Alec is too far gone to care if it’s embarrassing.

“Please,” he stutters out, trying to catch his breath as the the tentacle flexes in him. “Please, Magnus, fuck my cock,” he begs, voice breaking on the last word.

Alec throws his head back with a sharp cry when the tentacle thrusts into him before pulling back, retreating until Alec thinks Magnus is going to pull out. But he doesn’t, it slides back in, halfway, out again, and Alec comes with a desperate sob.

It feels strange. He can feel his cock jerking in the grip of Magnus’s fist and contracting around the intrusion, body working  _ harder  _ and they’ve done enough play with orgasm delay for Alec to appreciate how fucking  _ good _ it feels.

“Alexander,” Magnus groans, and Alec doesn’t know why until Magnus tilts his head so Alec can finally get a look at what Magnus is doing to him.

His come is dripping wetly from his cock, bubbling up around the tentacle filling him up, and when it thrusts further  _ in, _ Alec  _ whines. _ “Magnus, Magnus,” he chokes out, even as Magnus slides in  _ deeper  _ and squeezes his cock again. It feels like his come is being forced out of him and he can't do anything but shake against Magnus as it happens.

Magnus strokes him through the last of his orgasm, shushing him gently. He’s crying, shuddery little sobs loud in the room.

“Did that feel good, darling?” Magnus says, pressing a soft kiss to his cheek and nuzzling him gently when Alec leans into the touch.

“Yes,” he says, trying to catch his breath and failing. “Fuck, Magnus, I—”

Alec loses his thread of thought and his ability to speak when the tentacle presses in just a  _ little _ more and touches his prostate from the  _ inside  _ in a way that makes his mind white out.

_ Oh, _ he thinks, and he doesn’t know if he says it, doesn’t know if he moans or  _ screams, _ because the tentacle is curled up in him and pressing against that spot deep inside him that makes him come  _ again. _

He starts crying again. The only thing keeping him pressed flush to Magnus are the tentacles wrapped around his body, another one joining the one on his hips as a heavy band across his chest.

He pants out Magnus’s name, over and over, but it just doesn’t  _ stop, _ not even when Magnus’s name turns into a litany of  _ ‘no’. _

It’s only when he feels like he’s on the verge of passing out from the pleasure that Magnus stops, tentacle uncurling in him and letting him go limp even as he whines at the loss.

“You made a mess,” Magnus purrs in his ear, and Alec is barely coherent enough to turn his head to look.

There’s a mess of come over the sheets and all over his cock, over Magnus’s  _ hand  _ and clinging wetly to the tentacle in him.

“Oh, angel,” Alec says, throat raw, even as his body still shakes, “Magnus, what—”

“I can hardly fill you up without making sure I won't hurt you when I do it, darling,” Magnus explains, like he hadn’t just milked Alec’s cock of so much come that it’s pooled on the sheets.

Alec lets his eyes fall closed because  _ they’re not done. _ They’re not done and he’s already wrecked, pushed to what feels like his limits, but he knows that’s not true.

There’s going to be  _ more, _ and Alec  _ wants it. _

“Magnus,” he breathes out weakly, voice cracking.

His cock feels so sensitive, whatever aphrodisiac the tentacles exude keeping him hard but that doesn’t change that he’s well beyond overstimulated.

When Magnus presses a finger against where the tentacle is breaching his cock he tries to jerk, not sure if he wants to get away or not.

“Good, darling?” Magnus asks, giving him a chance to stop this now, before they go any further. To decide that they’ll try this again, later, and not all at once.

Alec is all about  _ all at once, _ though. Doesn’t know the meaning of waiting, not unless Magnus  _ makes him. _ Magnus unlocked something greedy and impatient in him and Alec  _ never _ wants to stop.

“Good,” he says, on the second try. “Good, please, don’t stop.”

Magnus presses a kiss to his temple and then there’s slick pulse inside his balls.

It’s only been a few hours, but somehow in that time he’d already forgotten how  _ hot _ it was. Heat spreads through him, tipping right over the edge into  _ too much. _

The high, strangled noise that leaves his mouth feels like it tears his ability to think out with it.

There’s only  _ heat, _ spilling deep into his body, too hot, too  _ much, _ and the feeling of his cock being stretched around the twitching length of tentacle filling him up.

He’s whimpering, soundless little puffs of air leaving his mouth as he pants desperately for air because he keeps forgetting to breathe.

He clenches down on Magnus’s cock, and feels Magnus groan in response instead of hears it, head filled with rushing noise.

The hot rush of sensation spills up his cock and drips out, streaking along the head of his cock, burning hot, before joining the mess on the bed.

When Magnus brushes his fingers through the mess and then  _ down _ on the tentacle where it’s joined into his cock, he goes completely limp, mouth open as he shudders through what feels like the most intense orgasm of his life.

Then Magnus curls the tentacle up into his prostate again and Alec nearly passes out, pleasure so sharp and intense that his entire body feels like a livewire, nerves sparking with it, so overwhelmed he almost feels numb.

It only lasts a few seconds before it’s  _ too much, _ in a real sense, but Magnus knows his body, better than Alec does some days. Before Alec can even try to string words together to tell Magnus to  _ stop,  _ the press of the tentacle on his prostate stops.

Alec is vaguely aware of Magnus’s hands soothing him, brushing gently over his sides as the tentacle uncurls and slips out of his cock with only a mild flash of discomfort with how strung out he is. 

When Magnus shifts, pulling out of him, Alec realises that his hole is wet. He clenches his muscles curiously and shivers at the feel of Magnus’s come dripping out. Alec hadn’t even realised Magnus  _ had  _ come and a soft moan leaves his mouth at the fact that he’d been so overcome with pleasure that he hadn’t even  _ noticed. _

“Darling,” Magnus murmurs gently, hand brushing gently across the base of his cock, making him whine. Everything’s still  _ hot, _ and after a confused moment he realises that’s because his cock is steadily leaking the come that Magnus had pumped into him.

He grasps weakly for Magnus’s hand and sighs a little when Magnus slips a hand into his, fingers tightening as much as he’s able to ground himself with Magnus as his anchor point.

“M’gnus,” he says, or tries to — he’s not sure if he actually managed the word or just a sound with the vague cadence of Magnus’s name — and Magnus shushes him again; then there’s cool blue magic soothing over his senses, dulling the electric tingling under his skin and soothing the heat dribbling out of his cock.

“You were so gorgeous, Alexander,” Magnus says, even as the magic fades, leaving Alec feeling uncomfortably empty and hallow. He squirms closer to Magnus with an discontented noise.

“Are you going to nap again?” Magnus asks, sounding amused. Alec pouts at him without opening his eyes or trying to answer.

“Sleep well, darling. Dream of me,” Magnus says, pressing a soft kiss to his lips.

_ Always, _ Alec thinks, already drifting off.

**Notes for the Chapter:**

> complaint: funishment isn't a tag? What are all the authors who write fics about brats DOING.
> 
> funishment is "fun punishment" and usually involves brats; in this case, it's magnus "punishing" alec by not letting him see what's going on until later on in their scene. which, you know, just made everything hotter for alec.
> 
> also this got really sweet at the end, i don't know.
> 
> feel free to point out spelling mistakes if you see them!
> 
> also you should all go read [blissfully unbounded](https://archiveofourown.org/works/20931065) by lynne_monstr, which is also a tentacle sounding fic and fucking _amazing_.


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